GXT MessageBox with scrollable content

I have to show a stacktrace using a GXT AlertMessageBox, and I would like to have a fixed-size box with the content being scrollable (at least vertically). Unfortunately I am not able to achieve that.

What I've done so far is the following :

use an @XTemplate like this
```
@XTemplate(value = "<pre>{stacktrace}</pre>")
SafeHtml render(String stacktrace);
```
to render the stacktrace. Here <pre> is needed to retain the stacktrace format.

Use a GXT AlertMessageBox to render the template like this :

MessageBox box = new AlertMessageBox("", "");
box.setMessage(StacktraceTemplate.RENDERER.render(stackTrace).asString());
box.setHeadingText("Stacktrace");
box.setResize(false);
box.setHeight(700);
box.show();

It seems to me that I can either :

have the container resize itself to the size of the content (if I let box.setResize(true), which is the default anyway)
have the container truncate the stacktrace to the size I specify by box.setHeight()

I have already tried the following :

have the template declaring overflow: scroll; (i.e. @XTemplate(value = "<pre style='overflow: scroll;'>{stacktrace}</pre>") and also @XTemplate(value = "<div style='overflow: scroll;'><pre>{stacktrace}</pre></div>")). The result is that I see a disabled scrollbar, and the content is still truncated.

wrapping the SafeHtml resulting from the XTemplate in an HTML, and then adding it to a ScrollPanel. Then I added the scrollpanel as the box's message this way :

ScrollPanel container = new ScrollPanel(content);
container.setAlwaysShowScrollBars(true);
HTMLPanel panel = new HTMLPanel("");
panel.add(container.asWidget());
MessageBox box = new MessageBox(SafeHtmlUtils.fromSafeConstant("<div>StackTrace</div>"),SafeHtmlUtils.fromTrustedString(panel.getElement().getInnerHTML()));
// same setResize, setHeight, show as before

but the result is the same (i.e. disabled scrollbar).

wrapping in a FlowLayoutContainer with getScrollSupport().setScrollMode(ScrollSupport.ScrollMode.ALWAYS);. Same result.

What should I do to have a fixed size MessageBox with scrollable content?

Solution

It turns out that I was quite near to a solution : the idea is to let the MessageBox adapt its size to the content, and then to fix the size of the ScrollPanel like this :

HTML content = new HTML(StacktraceTemplate.RENDERER.render(stackTrace));
ScrollPanel container = new ScrollPanel(content);
container.setHeight("700px");
HTMLPanel panel = new HTMLPanel("");
panel.add(container.asWidget());
MessageBox box = new AlertMessageBox(
    SafeHtmlUtils.fromSafeConstant("<div>StackTrace</div>").asString(),
    SafeHtmlUtils.fromTrustedString(panel.getElement().getInnerHTML()).asString());
box.show();